University of Colorado Solar Decathlon House from 2005, Washington DC...

University of Colorado, Denver and Boulder 

(THE FOLLOWING text by Susan Moon, Ruby Nahan, Cécile Warner, Michael Wassmer of the National Renewable Energy Laboratory)

"The University of Colorado’s entry emphasizes natural materials throughout, as you might expect of a team from scenic Colorado. Although the university took top honors overall in the 2002 competition, the 2005 team didn’t rest on its laurels. Instead, they worked hard to design, construct, and demonstrate an original, sustainable modular home concept.

When they got to the National Mall, the team worked even harder. Faculty Advisor Mike Brandemuehl said they were the first to arrive and the last to leave each day of the competition. The Colorado team drove their GEM (electric car) as if their lives depended on it, because one never knew when an extra point or two would be needed.

Colorado’s home features a movable roof constructed of custom steel struts that lowers for ease of travel and lifts for a feeling of openness and increased lighting when the house is stationary. Photo by John Millard 

Colorado’s home features a movable roof constructed of custom steel struts that lowers for ease of travel and lifts for a feeling of openness and increased lighting when the house is stationary. Photo by John Millard 

What’s Different?

• For the walls, the team combined two off-the-shelf “green” building components into one newly patented SIP. Colorado’s “BIOSIP” is like a giant
ice cream sandwich made of two panels of Sonoboard—a strong but lightweight board made of recycled materials by Sonoco Company—that are filled with BioBase 501, a lightweight foam insula- tion made from soybean oil by BioBased Systems.

• Most of the home’s furnishings, and even the tableware, are made of natural mate- rials such as corn, wheat, soy, and even coffee. Building on this, the team used food-related metaphors in their commu- nications pieces as “branding” elements.

• The team transported the home to and from Washington, D.C., primarily using a biofuel—B100 (pure) biodiesel.

Architecture, Interior Comfort

• A radiant-heat floor and well-insulated walls (R-30 to R-35) provide uniform levels of interior warmth and comfort.

• A “solar hearth” that contains the home’s mechanical systems adds to its interior attractiveness.

• The home is designed to be highly acces- sible to the public, including people with disabilities.

• A movable roof constructed of custom steel struts lowers for ease of travel and lifts for a feeling of openness and increased lighting when the house is stationary.

Heating and Cooling Systems

• A ductless, nonintrusive heating, ventila- tion, and air-conditioning (HVAC) sys- tem provides cooling for the home. 

The evacuated tube solar thermal water   heating system is designed to provide   heat both for domestic hot water and for the integrated radiant floor system.   The rooftop PV system comprises 32 SunPower 200-watt (W) solar panels that are 16% efficient. OutBack Power Systems donated the balance of the PV system. Photo by John Millard

The evacuated tube solar thermal water heating system is designed to provide heat both for domestic hot water and for the integrated radiant floor system. The rooftop PV system comprises 32 SunPower 200-watt (W) solar panels that are 16% efficient. OutBack Power Systems donated the balance of the PV system. Photo by John Millard

PV and Solar Thermal

  • The evacuated tube solar thermal water heating system is designed to provide heat both for domestic hot water and for the integrated radiant floor system.

  • The rooftop PV system comprises 32 SunPower 200-watt (W) solar panels that are 16% efficient. OutBack Power Systems donated the balance of the PV system.

  • The home demonstrates building- integrated PV via the PV awnings that provide electricity for the home as well as shade for its windows.

    The 2005 Colorado team matched its 2002 counterpart by winning the Communica- tions contest. Both the Web site panelists and the House Tour panelists unanimously chose Colorado as the winner. The team used creative and accessible ways of com- municating on their Web site and within their house. The judges found the Web design to be clean and fresh, while their writing style on the Web was snappy, fun, and clear, covering a lot of content. The House Tour judges echoed the praise: “This team’s entire focus seemed to be interacting with the public. Food was a very effective branding mechanism. The tour connected with the technologies... this is the team who figured out who the audience is.”

    It was evident that the Colorado team communicated well not only with the outside world, but also with each other. The members of this team were clear on their roles and committed to each other and to the goals of the competition.

    Colorado also set the standard for Docu- mentation by winning that contest, which evaluates the quality of documents sub- mitted for the schematic design, design development, construction, and “as-built” phases of the Solar Decathlon project. 

The team performed well in all four com- ponents of this contest, a proven key to overall success. In particular, the energy analysis report was, in the words of the judges, “a tour-de-force.” One judge said, “This is how it should be done!”

Key to this team’s overall success, and their eventual victory, was their use of strategy and the ability to function in spite of the rainy weather. On Tuesday, October 11, at 8:00 a.m. they decided to “live in the house,” which meant operat- ing the system the way a homeowner would normally do in a rainy situation and draw from the batteries. But they
had also planned well. “We focused on designing for a 40-year model worst case weather scenario. That’s why we’re doing okay now,” said Colorado team member Kristin Field, when presenting to the Engi
- neering panel of judges.

They looked at the scoring spreadsheet, considered the weather, calculated the number of points they could gain in which contests, and developed a strategy to win. Like all good competitors, they gamed it well.

First, they took a long hard look at the scoring spreadsheet to determine which achievements would give them the most

points. They sacrificed the Energy Balance contest to focus on contests that required energy usage. To ensure success in their strategy, they took a gamble on the weather. But they also looked at about five different weather reports each day, just in case they needed to change strategies.

They knew how best to drive the car, and the best time to charge it. Student team member Frank Burkholder was their GEM specialist. He made it his job to know how to get the best mileage out of the car. 

During the summer prior to the competi- tion, Scott Horowitz, Colorado’s calm and patient driver, and Burkholder drove hundreds of miles to determine the best charging per mileage scheme. They found that driving a slow and steady 15 mph/ 24 km/h gained the most miles/kilometers per charge. Each day during the compe- tition, Colorado set the bar for points awarded in the Getting Around contest, and ended up winning that contest handily.

The team also did a lot of other things right. They scored well in many of the judged contest activities. They planned for a battery bank that could get them through a week of cloudy weather. Their energy storage allowed them to score well in Getting Around in addition to the Appli- ances and Hot Water contests.

Along with the overall Solar Decathlon victory, the Colorado team received two special awards. BP, a Solar Decathlon sponsor, presented the team with its Brand Value Award for being “green” and dem- onstrating environmental leadership. And DIY Network, also a Decathlon sponsor, bestowed the Best Built Home Award on the Colorado house. 

After the competition, the team transported the house to the Colorado campus, where it will be displayed for about a year as a tool for education and outreach. Then the house will be delivered to its purchaser— Prospect New Town in Longmont, Colorado—a New Urbanist community featur- ing sustainable, green-built residences. "

-(THE ABOVE TEXT BY SUSAN MOON, RUBY NAHAN, CÉCILE WARNER, MICHAEL WASSMER OF THE NATIONAL RENEWABLE ENERGY LABORATORY)